Many wireless applications use packet data service option 33 in a CDMA2000 network as a basic packet data transport over which user data may be transmitted. For some applications, the base station needs to be able to look at the contents of the user data in order to handle some packets differently for various reasons. However, the contents of the user data are not readily available at the base station because the user data is embedded inside the Point-to-Point protocol (PPP) header. Parsing through the PPP header to access the user data at the base station is computationally intensive and relatively complex.
Currently, in order to obtain a type-of-service bit, for example, the base station has to parse through an external IP header, a GRE header, a PPP header and the IP header. In order to do this, the base station has to incorporate complex algorithms to handle all possible PPP header and user data parameters, including various types of compression, because the base station has no knowledge of the negotiated parameters that were used in setting up the PPP session between the packet data server node (PDSN) and the mobile station.
Parsing the PPP frame and the IP datagram is a processor-intensive procedure because the base station has to parse every single octet that comes from the PDSN. In addition, detecting a PPP flag sequence is a CPU-intensive task, which is normally done using a hardware-assisted HDLC de-framer. Any errors in the bit stream or parsing would falsely trigger the wrong handling of the communication session by the base station, which would be detrimental to the call setup latency.
Furthermore, more processing at the base station means that time-critical, high-priority messages are delayed even more due to the additional processing. For example, a delay in detecting a high-priority message at the base station could result in a call state transition at the mobile station and the base station. This new call state could essentially make the message that was supposed to be received obsolete.
Therefore, there is a need in the art for an improved method for prioritizing IP traffic in a wireless network based on a type-of-service identifier. In particular, there is a need for an improved wireless network that reduces the amount of time needed to determine the type of service for a particular communication session.